CPython compiles to a byte code, too and runs that (https://devguide.python.org/internals/interpreter/)

Any speed difference between the two is because of a combination of

- developers spending less effort on making it fast

- differences in the virtual machines instruction set

- differences in the languages that make one harder to run fast

I think/guess the first is the major reason, but the instruction set may matter, too. The last one has at most a minor impact.

A reason developers spend less time making the CPython interpreter faster is that you can relatively easily make ‘python’ even faster by making it call C code.